This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 11-282401, filed Oct. 4, 1999, the entire contents of which are incorporated herein by reference.
The present invention relates to a communication system and communication channel coupling method. In the communication system, more than one multimedia terminal (customer terminal) connected to a public network and having a function to send/receive audio or video or audio and video information, a multimedia terminal (operator terminal) located on a LAN (Local Area Network) and having a function to send/receive audio and video information, a public network connection unit having a function to send/receive information between a public network and a LAN, or a plurality of multimedia terminals and a plurality of public network connection units are arranged on a network. According to the present invention, the communication system is allowed to provide connection control between the multimedia terminals, between the multimedia terminal and the public network connection unit, or between the public network connection units.
Along with the evolution of Internet, increased is the number of systems wherein various desired types of information services are acquired through access to the computers of information service providers from users"" terminals. Furthermore, information services and commodity transactions are conducted with vocal answer while users dial up the computer systems of service providers from their telephones.
FIG. 13 is a diagram showing a conventional system configuration designed to interconnect operator terminals and user terminals. The information service system is provided with operator terminals 110 and 120, a server 100 which stores various types of service information and control information, and a PBX (Private Branch Exchange) 130 which performs information switching connections. The PBX 130 is connected to user terminals 150 and 160 via a public network 140, and connection between the operator terminals 110 and 120 and the user terminals 150 and 160 is performed by the PBX 130.
For example, if the user terminal 150 issues a communication request, the PBX 130 receives it and searches the server 100 to find an idle operator. Once the connection between that operator terminal (e.g., 110) and the PBX 130 is established, information communication is held between the operator terminal 110 and the user terminal 150 via the PBX 130. When the operator terminal 120 needs to generate a call, it searches the server 100 to acquire the telephone number of the user terminal. Once the connection between the operator terminal 120 and the PBX 130 is established, the PBX 130 calls the user terminal (e.g., 160) via the public network 140, and after its answer is confirmed, information communication is carried on between the operator terminal 120 and the user terminal 160.
In conventional information service systems, the PBX performs control on connections between terminals. For this reason, the conventional systems accommodate a dedicated unit to interconnect a switching unit and trunk lines for transmission and reception of audio and video information. There is no system implemented wherein audio and video information from a users"" telephone or a personal computer terminal connected to a public network is received at an operator terminal via a LAN in a computer system; or audio and video information from an operator terminal is transmitted to a users"" telephone or a personal computer terminal via a LAN in a computer system and, further, via a public network. For this reason, it is necessary to go through a dedicated PBX in order to establish information communication between a user terminal and an operator terminal, which made the system very costly.
This invention has been made in view of the situation described above, and allows to build up an information providers"" computer system with a server computer, etc. And, more than one operator terminal, more than one public network connection unit, and a control unit which controls connections (e.g., a call-generating unit, an answering unit, a connection control unit, a terminal, etc.) are connected on a LAN, so that the units interconnected on the LAN can hold high-speed communications between themselves by means of packet communication using TCP (Transmission Control Protocol), UDP (User Datagram Protocol), etc., and the public network connection unit and user terminals on the public network can perform conventional telephone line communications. Consequently, it is an object of the invention to provide a communication system and communication channel coupling method that can establish connection between user terminals (via a public network connection unit) and operator terminals, connection between operator terminals, and connection between user terminals (via two public network connection units) by simple procedures.
According to a first aspect of the present invention, there is provided a communication channel coupling method in a communication system wherein one or a plurality of multimedia terminals having a function to send/receive audio or video or audio and video, one or a plurality of public network connection units having a function to send/receive audio and video between the multimedia terminal and the public network connection unit or between a public network and a LAN, and a control unit are arranged on the LAN,
the method being arranged to provide connection between the multimedia terminals, between the multimedia terminal and the public network connection unit, or between the public network connection units, and comprising the steps of:
causing the control unit to send a call setup request to a first connection unit, and then to record audio and video communication channel information of the first connection unit which is obtained in response to the call setup request, so as to establish an audio and video communication channel;
causing the control unit to send the call setup request to a second connection unit, and then to record audio and video communication channel information of the second connection unit which is obtained in response to the call setup request, so as to establish an audio and video communication channel;
causing the control unit to send the audio and video communication information of the second connection unit to the first connection unit;
causing the control unit to send the audio and video communication information of the first connection unit to the second connection unit; and
establishing communication between the first connection unit and the second connection unit.
According to the first aspect, it is readily possible to implement communication coupling by sending a call setup request from a control unit (e.g., an automatic call-generating unit, an automatic answering unit, a connection control unit, a terminal, or a unit comprising a combination thereof) to the first and second connection units desired to interconnect, and mutually indicating the communication channel information contained in their answer signals.
According to a second aspect of the present invention, there is provided a communication channel coupling method in a communication system wherein one or a plurality of multimedia terminals having a function to send/receive audio or video or audio and video, one or a plurality of public network connection units having a function to send/receive audio and video between the multimedia terminal and the public network connection unit or between a public network and a LAN, and a control unit are arranged on the LAN,
the method being arranged to provide connection between the multimedia terminals, between the multimedia terminal and the public network connection unit, or between the public network connection units, and comprising the steps of:
causing the control unit to send a first call setup request to a first connection unit, and to mutually send/receive communication channel information therebetween;
causing the control unit to send the first call setup request to a second connection unit, and to mutually send/receive communication channel information therebetween;
causing the control unit to send a transfer request to the first connection unit, after communication between the control unit and the first and second connection units is established;
causing the first connection unit, which has received the transfer request, to send a second setup request to second connection unit, so as to cause the first and second connection units in response thereto to mutually send/receive communication channel information therebetween through the control unit;
causing the first and second connection units to disconnect communication with the control unit, after the first and second connection units mutually receive the communication channel information therebetween; and
establishing communication between the first connection unit and the second connection unit.
According to the second aspect, it is readily possible to implement communication coupling by sending a call setup request from the control unit to the first and second connection units desired to be interconnected, by receiving the communication channel information contained in their answer signals, and thereafter, by indicating the mutual communication channel information between the first connection unit and the second connection unit, pursuant to a communication channel transfer request, while disconnecting all the communication channels between the control unit and the first connection unit and between the control unit and the second connection unit.
According to a third aspect of the present invention, there is provided a communication channel coupling method in a communication system wherein one or a plurality of multimedia terminals having a function to send/receive audio or video or audio and video, one or a plurality of public network connection units having a function to send/receive audio and video between the multimedia terminal and the public network connection unit or between a public network and a LAN, and a control unit are arranged on the LAN,
the method being arranged to provide connection between the multimedia terminals, between the multimedia terminal and the public network connection unit, or between the public network connection units, and comprising the steps of:
causing the control unit to send a call setup request to first and second connection units, and to mutually send/receive communication channel information therebetween;
causing the control unit to send the communication channel information of the second connection unit and a communication channel change request to the first connection unit, and to send the communication channel information of the first connection unit and the communication channel change request to the second connection unit, after communication between the control unit and the first and second connection units is established;
causing the first and second connection units, which have received the communication channel change request, to record the communication channel information of the second and first connection units, respectively, and to terminate communication with the control unit; and
establishing information communication through a communication channel thus changed between the first connection unit and the second connection unit.
According to the third aspect, it is possible to couple a communication channel for audio and video signals between the first connection unit and the second connection unit desired to interconnect, while the control line between the control unit (e.g., a call-generating unit, an answering unit, a connection control unit, or a terminal, etc.) and the first and second connection units is held on, by sending a call setup request from the control unit to the first and second connection units, by receiving the communication channel information contained in the received answer signals and establishing the connection, and by indicating the communication channel information and communication channel transfer request of the second connection unit to the first connection unit, and indicating the communication channel information and communication channel transfer request of the first connection unit to the second connection unit.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.